DOCUMENT:Q140105  06-MAY-2001  [visualc]
TITLE   :PRB: Assertion While Switching Property Pages in OLE Control
PRODUCT :Microsoft C Compiler
PROD/VER:winnt:2.0,2.1,2.2,4.0
OPER/SYS:
KEYWORDS:kbActiveX kbCOMt kbCtrlCreate kbMFC kbPropSheet kbVC200 kbVC210 kbVC220 kbVC400 kbGrpDS

======================================================================
-------------------------------------------------------------------------------
The information in this article applies to:

 - The Microsoft Foundation Classes (MFC), used with:
    - Microsoft Visual C++, 32-bit Editions, versions 2.0, 2.1, 2.2, 4.0 
-------------------------------------------------------------------------------

SYMPTOMS
========

If you have implemented an OLE control that uses a basic MFC CPropertySheet as a
user interface, you may receive the following error when trying to switch pages
by clicking the tab:

   Assertion Failed
   OC30D.DLL: File DlgCore.CPP Line 194

CAUSE
=====

This assertion occurs in _AfxCheckDialogTemplate, when MFC cannot find the
dialog template resource for the property page.

RESOLUTION
==========

The solution is to override CPropertyPage::OnSetActive and use AFX_MANAGE_STATE
as in the following code:

Sample Code
-----------

      /* Compile options needed - none
         Add the following code to each of your CPropertyPage-derived classes.
      */ 
      BOOL CYourPropPage::OnSetActive()
      {
        AFX_MANAGE_STATE(_afxModuleAddrThis);
        return CPropertyPage::OnSetActive();
      }

The prototype for OnSetActive must also be added to your CPropertyPage- derived
class header file.

REFERENCES
==========

For information on AFX_MANAGE_STATE, please see the following article in the
Microsoft Knowledge Base:

   Q127074 How to Use AFX_MANAGE_STATE in an OLE Control

Additional query words: kbvc200 kbvc210 kbvc220 kbvc400 kbmfc

======================================================================
Keywords          : kbActiveX kbCOMt kbCtrlCreate kbMFC kbPropSheet kbVC200 kbVC210 kbVC220 kbVC400 kbGrpDSMFCATL kbNoUpdate 
Technology        : kbAudDeveloper kbMFC
Version           : winnt:2.0,2.1,2.2,4.0
Issue type        : kbprb

=============================================================================

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS
PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND.  MICROSOFT DISCLAIMS
ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  IN NO
EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR
ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL,
CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF
MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE
POSSIBILITY OF SUCH DAMAGES.  SOME STATES DO NOT ALLOW THE EXCLUSION
OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES
SO THE FOREGOING LIMITATION MAY NOT APPLY.

Copyright Microsoft Corporation 2001.